General Information

P0116 Engine Coolant Temperature Circuit Range / Performance

General Information

Component Location





General Description

The Engine Coolant Temperature Sensor (ECTS) is located in the engine coolant passage of the cylinder head for detecting the engine coolant temperature. The ECTS uses a thermistor whose resistance changes with the temperature. The electrical resistance of the ECTS decreases as the temperature increases, and increases as the temperature decreases. The reference 5 V in the PCM is supplied to the ECTS via a resistor in the PCM. That is, the resistor in the PCM and the thermistor in the ECTS are connected in series. When the resistance value of the thermistor in the ECTS changes according to the engine coolant temperature, the output voltage also changes. During cold engine operation the PCM increases the fuel injection duration and controls the ignition timing using the information of engine coolant temperature to avoid engine stalling and improve drivability.

DTC Description

Checking the engine coolant temperature under detecting condition, if the engine coolant temperature's signal is temporarily stuck above the lowest enable temperature to enable other diagnostic or the coolant temperature exceeds the threshold temperature under normal operation loads or the difference between its current temperature and startup temperature is less than threshold value over predeterminated period, PCM sets P0116.

DTC Detecting Condition





Specification





Diagnostic Circuit Diagram





Signal Waveform & Data












Fig.1) Normal waveform of ECTS at 77 °C (171.1 °F)
Fig.2) Normal data of IATS & ECTS & EOTS at ig on
Fig.3) Normal data of IATS & ECTS & EOTS after warming up.

The output signals of IATS & ECTS change smoothly without any rapid changes. These 2 sensor have almost the same characteristic signal during the early period after start. It means that the temperatures of intake air and engine coolant are depended on the temperature of atmosphere. Meanwhile, During engine warm up the output signal of the ECT will change quicker than the IAT signal. even it may not change almost.